Method of controlling a differential motor torque steering system of a working machine and system thereof

A method of controlling a steering motion of an agricultural machine, comprising:

• providing the agricultural machine with a controller, a steer input sensor, a machine speed sensor, a motor displacement input, a prime mover for propelling the machine in a travel direction, a primary differential steering system for operably controlling a front traction mechanism, and a secondary steering system comprising a first actuator for controlling a first rear wheel and a second actuator for controlling a second rear wheel;
• detecting a machine speed with the machine speed sensor, a position of the steering wheel with the steer input sensor, and a motor displacement level from the motor displacement input;
• determining a first gain value as a function of the machine speed and motor displacement level;
• determining a steer command comprising a first steer direction and a first steer rate;
• determining a second gain value based on the motor displacement level and first steer rate;
• calculating a control signal based on the first gain value and the second gain value;
• outputting the control signal to a steering valve of the secondary steering system, wherein the control signal comprises a rear steering gain that is a function of machine speed and the motor displacement level;
• actuating the first and second actuators based on the control signal;
• and
• operably controlling the first and second rear wheels to cause the steering motion of the agricultural machine.